Chemical sterilization uses a sterilizing fluid such as hydrogen peroxide, ethylene oxide, chlorine dioxide, peracetic acid, or a combination thereof. A plasma may be induced to enhance the sterilization process. Although chemical sterilization is normally effective, it is difficult for cleaning and sterilizing fluid to penetrate to the contact area of the device to be sterilized. It also may not be as effective with medical devices containing long, narrow tubes, or lumens. Sterilization of these long lumens requires that the sterilizing agent penetrate the entire length of the long narrow tube. It is difficult for the sterilizing agent to completely penetrate these long narrow tubes. In order to enhance the penetration of the sterilizing agent down the entire length of the lumen, several forms of apparatus have been developed to flow sterilizing agent through the length of the lumen, thus enhancing the effectiveness of the sterilizing treatment.
For example, U.S. Pat. Nos. 4,410,492 and 4,337,223 describe a sterilization method in which the lumen is placed in a socket connected to a valve and a recirculating pump. The sterilizing gas is recirculated from the sterilization chamber through the lumen of the instrument. Although the method is effective at sterilizing the lumen, sterilization of endoscopes requires 2-3 hours using ethylene oxide as the sterilizing gas.
A method which delivers sterilizing agent down long, narrow lumens is described in U.S. Pat. No. 5,580,530. The lumen is inserted into an adaptor connected to a vessel containing hydrogen peroxide called the booster. The lumen, adaptor, and booster are all placed in the sterilization chamber. When the sterilization chamber is evacuated during the sterilization procedure, the hydrogen peroxide in the booster vaporizes and passes through the lumen, thereby sterilizing the interior of the lumen.
During use of the various sterilization methods, there are always areas of contact between the device to be sterilized and a holding or supporting means. It is difficult for a fluid such as a cleaning solution or a sterilizing agent to penetrate into these contact areas. Thus, the contact area usually can not be sterilized efficiently in a conventional sterilization process.
There is a need for a method of enhancing the penetration of washing, rinsing and/or sterilizing fluids into these contact areas, or significantly reducing or totally eliminating the occluded area to allay any potential concerns about incomplete sterilization.